The Best Oil for Roast Potatoes

Written by Ross Bearman, founder of Ross & Ross Gifts and a Great Taste judge with over 25 years in fine food.

Why cold pressed rapeseed oil makes the crispiest roast potatoes

Crispiness is a heat problem, not a fat problem.

When a parboiled potato hits the tray, you want the outer layer of starch to dehydrate and set fast. If the oil is not hot enough, the potato sits and absorbs it, and you end up with something greasy and pale. If the oil is hot enough, the surface moisture flashes off, the roughed up edges seize into a shell, and the inside steams itself fluffy.

So the number that matters is smoke point. That is the temperature at which an oil starts to break down, smoke and taste acrid. Once an oil passes its smoke point you cannot push it any harder, which means you cannot push the potato any harder either.

Cold pressed rapeseed oil sits near the top of the range at roughly 230C. That is comfortably above a domestic oven at full tilt, which is exactly what you want. It gives you headroom. You can get the tray screaming hot, hold it there, and never worry about the fat turning on you.

Duck fat and goose fat, for all their reputation, sit lower at around 190C to 200C. Beef dripping is around 205C. Extra virgin olive oil is lower still. Those fats taste wonderful, but they cap your temperature, and temperature is what makes the crunch.

"Now the potatoes are prepared, it's time to choose what fat to cook them in. You want an oil or fat that has a high smoke point which means you can heat up really high to get super crispy roast potatoes."

The flavour problem, and how we solved it

Roast Potato Oil did not start as an oil. It started with duck.

"It all started from an old product and making Duck Rillettes, which used duck fat along with rosemary and garlic to confit the duck legs. This left over fat was wonderfully flavoured with meatiness and fragrant rosemary and garlic. And when used for making roast potatoes, created an incredible flavour. But the potatoes were never the crispiest they could be as the fat would evaporate or set on fire if heated too high."

That is the trade off every cook runs into. The fat that tastes best is the fat that performs worst under real heat.

So we went the other way. We started with the best performing fat and built the flavour back in. We sourced extra virgin, cold pressed Cotswold rapeseed oil, then smoked it and infused it with rosemary and garlic to recreate the savoury, umami depth you get from confit duck fat.

The result is an oil that behaves like a high performance frying medium and tastes like something that has been sitting under a roasting joint all afternoon. It was named Food Product of the Year at the Cotswold Life Food and Drink Awards. And because there is no animal fat in it at all, it is suitable for vegans and vegetarians.

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Best oil for roast potatoes UK: every option ranked

Here is how the common choices compare. Smoke points are approximate and vary by refinement and brand.

Oil or fat	Approx smoke point	Flavour	Vegan	Verdict
Cold pressed rapeseed oil	Around 230C	Mild, nutty, does not overpower	Yes	Best all round. Highest crisp potential.
Roast Potato Oil (smoked rapeseed with rosemary and garlic)	Around 230C	Smoked, savoury, herby, umami	Yes	Best of both. Crisp of rapeseed, flavour of animal fat.
Ghee	Around 250C	Rich, nutty, dairy	No	Excellent heat tolerance. Not vegan, and the dairy note is divisive.
Sunflower or vegetable oil	Around 225C	Neutral, almost none	Yes	Works well. Crisps fine but adds nothing to the taste.
Beef dripping	Around 205C	Deep, beefy	No	Great flavour, lower ceiling. Traditional Sunday roast choice.
Goose fat	Around 200C	Rich, savoury	No	Classic Christmas fat. Flavour beats function.
Duck fat	Around 190C	Rich, meaty	No	Superb taste, but it will smoke before you get maximum crunch.
Extra virgin olive oil	Around 190C	Grassy, peppery, assertive	Yes	Lovely flavour, wrong tool. Too low for high heat roasting.

One tip from the ebook that is worth repeating: you do not have to pick just one.

"TIP: Why not try a mix of fats. Duck fat and Rapeseed Oil has been a wonderful success."

Best oil for roast potatoes: sunflower or vegetable?

Sunflower oil and generic vegetable oil are effectively interchangeable for roasting. Both are refined, both are neutral, and both have a smoke point of around 225C, which is high enough to produce a crisp potato.

The difference is what they leave behind, which is nothing. A neutral oil does its job and disappears. If you are serving potatoes alongside a rich gravy and a big joint of meat, that may be all you need.

Cold pressed rapeseed oil sits slightly higher on smoke point and brings a gentle nuttiness that flatters the potato rather than masking it. If you want the potato itself to taste of something, that is the upgrade. Roast Potato Oil is a straight swap for the sunflower oil you are using now, same job, considerably more flavour.

Best oil for roast potatoes: vegetable or olive?

For high heat roasting, vegetable oil wins on performance and olive oil wins on flavour.

Extra virgin olive oil starts to break down at around 190C, which is below the temperature you want for a properly blistered roast potato. Push it and you get bitterness. Refined or light olive oil copes better, but at that point you have stripped out most of the flavour you were paying for.

"Olive oil: This is a good option but due to its slightly lower smoke point, does not make it great for roasting at high temperatures. But it adds a delicious flavour to the potatoes."

If you love olive oil with potatoes, use it for slow roasted new potatoes or a tray of crushed potatoes at 180C. For maximum crunch at 200C and above, use rapeseed.

Best oil for roast potatoes for vegetarians and vegans

Cold pressed rapeseed oil is the best oil for vegan and vegetarian roast potatoes, and it is not a compromise. It outperforms goose fat, duck fat and beef dripping on smoke point, which means a vegan roast potato can be crispier than a traditional one, not merely as good.

The only thing missing from a plain oil is the savoury depth. That is a flavour gap, and flavour gaps can be filled.

Smoke provides the roasted, over the coals note that people associate with meat. Garlic provides sweetness and body when it cooks down. Rosemary provides the woody, resinous aroma of a Sunday roast. Put all three into cold pressed rapeseed oil and you have covered the ground that duck fat used to cover.

That is exactly what Roast Potato Oil is. It is the reason we hear from vegans and vegetarians who tell us it is the first time their roast potatoes have tasted like the ones they remember.

Best oil for roast potatoes in an air fryer

Cold pressed rapeseed oil is also the best oil for air fryer roast potatoes, for the same reason it wins in the oven. Air fryers run hot and move air fast, so an oil with a low smoke point will burn off and taste bitter before the potato has finished.

Two things change in an air fryer. You need far less oil, and you cannot preheat the fat in the same way, because there is no deep tray of it to heat.

The method further down this page adapts easily. Full air fryer instructions are in the roasting section below. The same oil works beautifully on air fryer jacket potatoes and chips.

How to make the best roast potatoes

This is the method from the ebook, condensed. There are three stages and none of them can be skipped: choosing, preparing, roasting. Most failed roast potatoes fail at stage two, not stage three.

Stage one: choosing the right potatoes

You want a floury, high starch potato. Starch is what turns fluffy inside and rough outside. Waxy potatoes hold their shape and stay dense, which is what you want in a salad and not what you want on a Sunday.

• Maris Piper. The most popular roasting potato in the UK, high in starch, fluffy, and it crisps up beautifully. This is our choice.
• King Edward. Creamy and fluffy with a slightly sweet flavour and a thin skin that crisps well.
• Desiree. Slightly sweet and nutty with a firmer texture. Holds its shape and gives a good crisp exterior.
• Rooster. Rich and earthy with a firm texture. A newer variety that has become popular for roasting.
• Yukon Gold. Not traditional in the UK but a great option. Buttery flavour, fluffy texture.

Stage two: preparing the potatoes

One kilogram of potatoes feeds four people.

1. Wash. Rinse under cold water to remove any dirt.
2. Peel. Take the skin off with a peeler. Peeled potatoes crisp better.
3. Cut. Cut into evenly sized chunks so they cook at the same rate. Larger potatoes into three, smaller ones into two.
4. Parboil. Into a large pot of heavily salted boiling water, as salty as the Mediterranean sea. Parboil on a medium heat for 10 to 15 minutes, until the edges are just starting to soften. Do not overcook them or they will fall apart.
5. Drain. Very gently, into a colander. Leave to cool for five minutes.
6. Shake. Once slightly cooled, give the colander a good but gentle shake to rough up the edges. Those roughed up edges are the surface area that turns into crunch.
7. Season and dry steam. Season all over with sea salt, then leave them to cool and steam on the side for at least 30 to 60 minutes.

"The dry steaming will create wonderful pockets and ridges that will go super crispy when roasting."

"TIP: You can leave to completely cool and leave in the fridge and use the next day if you want to get ahead with prep."

That dry steaming step is the one almost everybody skips, and it is the single biggest difference between a good roast potato and a great one. Wet potatoes steam in the oil. Dry potatoes fry in it.

Stage three: roasting your potatoes

1. Preheat the oven to 200C (400F). Add your oil to a roasting tin, around half a centimetre deep, enough to cover the bottom of the tray. Put the tray in the oven for at least ten minutes. You want the oil very hot.
2. Take the tray out and put it on the hob. Keep the oil hot and almost smoking.
3. Carefully add the potatoes. Leave plenty of space around each one. A crowded tray steams. Use two trays if you need to.
4. Toss gently until evenly coated. Leave to cook on one side for one minute, then turn. Sprinkle with sea salt and return to the oven.
5. Cook for around 25 minutes.
6. Remove and place back on the hob. Turn the potatoes.
7. Return to the oven for about 20 minutes, or until golden brown and crispy outside and tender inside.
8. Drain onto kitchen paper to absorb any excess oil.
9. Hold in a low oven on a dry tray or cooling rack until you are ready to serve. Serve immediately if you can. Season with sea salt to taste.

"TIP: if you want to add extra flavour, you can add fresh ingredients like rosemary and garlic to the roasting tray. Add them ten minutes before the end of the cooking so they give off their fragrance but don't burn."

How to make the best roast potatoes in an air fryer

Stages one and two are identical. Choose a floury potato, parboil, shake, season, dry steam. Only the cooking changes.

1. Preheat the air fryer to 200C for three minutes.
2. Toss the dry steamed potatoes in two to three tablespoons of cold pressed rapeseed oil or Roast Potato Oil. You need far less than in the oven.
3. Load the basket in a single layer. Overcrowding is the most common air fryer mistake and it is fatal to crispiness. Cook in two batches rather than one crowded one.
4. Cook for 25 to 30 minutes, shaking or turning every 10 minutes.
5. Add a sprig of rosemary and a few crushed garlic cloves for the last five minutes.
6. Season with sea salt and serve straight away.

Air fryer potatoes come out drier and slightly more uniform than oven potatoes. They will not have the deep golden edges that a hot tray of oil produces, but they are quick and they are very good.

Should you boil potatoes before you roast them?

Yes. Parboiling is not optional if you want crispy roast potatoes.

Boiling does two jobs. It softens the outer few millimetres so that shaking the colander can break that layer into a rough, floury coating, and it partly cooks the inside so the potato does not need a punishing amount of oven time to become tender.

Roast a raw potato and the outside will be leathery rather than crisp, because there is no broken starch layer to crisp. The rough surface is the crunch. You cannot get it without boiling first.

Parboil in heavily salted water for 10 to 15 minutes, until the edges just start to soften. Stop there. Overboiled potatoes disintegrate in the colander.

What is the secret to perfectly crispy roast potatoes?

There is no single secret. There are five, and they compound.

1. Surface area. Parboil, then shake the colander to rough up every edge. Smooth potatoes have nothing to crisp.
2. Dryness. Let the potatoes cool and dry steam for 30 to 60 minutes before they go anywhere near oil. Surface moisture is the enemy of crunch.
3. Heat. Preheat the oil in the tray for at least ten minutes until it is almost smoking. The potato should sizzle the moment it lands.
4. An oil that can take that heat. Cold pressed rapeseed at around 230C gives you the headroom. A low smoke point fat caps how hard you can push.
5. Space. A crowded tray traps steam. Give every potato room, and use two trays if you have to.

Get all five right and the potato does the rest.

How to make your roast potatoes really crispy: the five most common mistakes

• Not salting the parboiling water enough. It should taste like the sea. This is the only chance the inside of the potato gets to take on seasoning.
• Going straight from colander to tray. Skipping the dry steam is the biggest single mistake in British home cooking. Give it half an hour.
• Cold oil. Adding potatoes to oil that has not been preheated means they absorb it instead of frying in it. Greasy, pale, disappointing.
• Too many potatoes on one tray. Steam has to go somewhere. If it cannot escape, it stays around the potato and softens the crust you are trying to build.
• Adding garlic and herbs too early. Forty five minutes at 200C will turn garlic bitter and black. Add it for the last ten minutes only.

Ways to serve

Once you have the ultimate roast potato, it does not have to sit next to a joint of beef. From the ebook:

1. Classic gravy alongside a traditional Sunday roast
2. Truffle cheese fondue and crispy bacon
3. Butter chicken curry and coriander
4. Grated parmesan and truffle oil
5. Chilli con carne, sour cream and pickled onions
6. Aioli and crispy calamari
7. Cheese and baked beans
8. Poutine, with cheese curds and gravy
9. Pulled pork with mango and chilli salsa
10. Hot smoked salmon and Bearnaise sauce

Or, as the book puts it, just a big bowl of deliciousness on their own.

Frequently asked questions

What is the best oil for roast potatoes in the UK?

Cold pressed rapeseed oil. It has a smoke point of around 230C, higher than goose fat, duck fat, beef dripping or olive oil, and a mild nutty flavour that does not overpower the potato. It is also British grown, which matters if you want a local ingredient.

Is rapeseed oil better than goose fat for roast potatoes?

For crispiness, yes. Goose fat smokes at around 200C while cold pressed rapeseed oil holds to around 230C, so rapeseed lets you roast harder. Goose fat has more flavour on its own. An infused rapeseed oil such as Roast Potato Oil closes that flavour gap while keeping the higher smoke point.

Can you make crispy roast potatoes without animal fat?

Yes, and they can be crispier. Cold pressed rapeseed oil outperforms goose fat, duck fat and beef dripping on smoke point. The only thing missing is savoury depth, which smoke, rosemary and garlic infusions restore.

Do you need to parboil potatoes before roasting?

Yes. Parboiling softens the outer layer so it can be roughed up into the floury surface that turns crispy. Without it the outside goes leathery rather than crunchy. Parboil in heavily salted water for 10 to 15 minutes.

How long should you leave potatoes to steam dry?

At least 30 to 60 minutes. You can also cool them completely and refrigerate overnight to get ahead. Dry potatoes fry in hot oil. Wet potatoes steam in it.

What temperature should you roast potatoes at?

200C or 400F. Preheat the oil in the tray for at least ten minutes first so it is almost smoking when the potatoes go in.

How long do roast potatoes take?

Around 45 minutes in total: 25 minutes, then turn, then a further 20 minutes until golden and crisp outside and tender inside.

Is Roast Potato Oil vegan?

Yes. Roast Potato Oil from Ross & Ross Gifts is cold pressed Cotswold rapeseed oil infused with smoke, rosemary and garlic. It contains no animal products and is suitable for vegans and vegetarians.

Can you use Roast Potato Oil in an air fryer?

Yes. Use two to three tablespoons to coat the potatoes, cook in a single layer at 200C for 25 to 30 minutes, shaking every 10 minutes. It works just as well on jacket potatoes and chips.

What potatoes are best for roasting?

Maris Piper is the best all round choice, with high starch and a fluffy texture. King Edward, Desiree, Rooster and Yukon Gold all work well.

About the author

Ross Bearman is the original founder of the food gifting company Ross & Ross Gifts, based in the Cotswolds. He is a Great Taste judge with over 25 years of experience in fine food, restaurants and creating premium food products for some of the country's finest retailers.

He has won multiple Gift of the Year and Great Taste awards, including the three star Great Taste award. Roast Potato Oil was created in pursuit of the ultimate roast potato and was named Food Product of the Year at the Cotswold Life Food and Drink Awards.

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